This invention generally relates to reclosable bags having slider-actuated plastic zippers. In particular, the invention relates to slider-actuated reclosable bags having a header or flap with holes or slits for mounting a stack of bags on a wicket.
Reclosable bags are finding ever-growing acceptance as primary packaging, particularly as packaging for foodstuffs such as cereal, fresh fruit and vegetables, snacks and the like. Such bags provide the consumer with the ability to readily store, in a closed, if not sealed, package any unused portion of the packaged product even after the package is initially opened.
Reclosable bags comprise a receptacle having a mouth with a plastic zipper for opening and closing. In recent years, many zippers have been designed to operate with a slider mounted thereon. As the slider is moved in an opening direction, the slider causes the zipper sections it passes over to open. Conversely, as the slider is moved in a closing direction, the slider causes the zipper sections it passes over to close. Typically, a zipper for a reclosable bag includes a pair of interlockable profiled closure strips that are joined at opposite ends of the bag mouth. The profiles of interlockable plastic zipper parts can take on various configurations, e.g. interlocking rib and groove elements having so-called male and female profiles, interlocking alternating hook-shaped closure elements, etc. Reclosable bags having slider-operated zippers are generally more desirable to consumers than bags having zippers without sliders because the slider eliminates the need for the consumer to align the interlockable zipper profiles before causing those profiles to engage.
Reclosable bags are commonly used by deli clerks in grocery stores to package cheese and deli meats sold to consumers. To facilitate handling of the reclosable bags by the deli clerks, the bags often include a header having one or more holes for mounting a stack of bags to one or more dispensing posts. The reclosable bags are typically mounted to the dispensing posts in bag packs consisting of a predetermined number of bags. The dispensing posts may, e.g., take the form of a U-shaped wicket wherein the legs of the U-shaped wicket penetrate respective holes formed in the header of each bag. The header may take the form of a top header extending upward from the zippered mouth of the bag or a bottom header extending downward from the bottom of the bag.
U.S. Pat. No. 5,682,730 discloses a plurality of plastic bags formed into unitary packs for shipping and loading onto dispensing posts. This is done by stacking the bags and then assembling them into a unitary pack by penetrating the stack with a heated or ultrasonic pin or punch element to form apertures. The bags in the pack are heat-welded or ultrasonically welded together along the periphery of the apertures. To maintain the integrity of the bag pack during shipping, the bag is mounted to dispensing posts in the form of a wicket prior to shipment.
More specifically, U.S. Pat. No. 5,682,730 discloses a reclosable bag having a bottom header with two holes for mounting the plastic bag to a pair of dispensing posts. The holes are spaced apart along a lateral line running generally parallel to the zipper. The bottom header includes a line of perforations that allows the bag to be torn away from the header after the bag has been filled with product. The embodiment illustrated in U.S. Pat. No. 5,682,730 has a bottom header that includes a pair of opposing header panels connected by a fold. The fold forms a primary bottom, while a seal line of thermal fusion forms a secondary bottom at the junction of the receptacle and the header. This patent further states that one of the header panels can be eliminated. The top of the bag U.S. Pat. No. 5,682,730 has a slider-actuated zipper. The zipper comprises two profiled zipper parts that have respective fins or flanges thermally fused to the inner surfaces of the receptacle panels.
An alternative to the aforementioned flanged zipper design is the so-called flangeless or string zipper, which has substantially no flange portions above or below the interlockable zipper strips. In the case of a string zipper, the bag making film is joined to the backs of the bases of the zipper strips. String zippers can be produced at much greater speeds, allow much greater footage to be wound on a spool, thereby requiring less set-up time, and use less material than flanged zippers, enabling a substantial reduction in the cost of manufacture and processing.
U.S. patent application Ser. No. 10/367,450 discloses a reclosable bag in which respective marginal portions of the bag film are sealed to the backs of respective flangeless zipper strips and in which the resulting string zipper is actuated by means of a slider.
There is a continuing need for new designs of wicketed reclosable bags that can be manufactured at low cost.